Painting Van's fiberglass spinner

The Van's spinner that came with my finish kit (or was it firewall forward?) seems to have a much smoother finish than the other fiberglass parts. My question is, does the spinner need to be sanded and finished for pinholes or would a light sanding and primer work? Thanks.

-John

The pinholes ARE there!

You will find the pinholes once you start sanding.

They may not all be the same

I did not sand or fill my spinner but I did the cowl. A year after making the initial flight, I flew to the painter's airport and left it in his capable hands. He said something about the primmer he used being able to fill minor imperfections. I don't know what the primer was but the paint was the Imron formulation in use in early 2005 with the clear top coat. It came out great and it has been the same for 5 years now. If there are pin holes beneath the finished surface (bubbles) I would not want to sand and start over with a pitted surface that you are going to have to fill and sand to get the smooth surface back. Paint adhesion is not a problem, which I think is your concern. If you have visible pin holes or glass cloth imperfections that have to be addressed before painting that is a different issue.

Bob Axsom

Wash

the spinner with water. There is likely a water soluable coating on the spinner -- possibly a mold release material. Once I cleaned this off, the spinner had a dull appearance with visible pinholes. Let us know what you find.

Best regards,

Bill
RV-7 N151WP
Lee's Summit, MO

Thanks to all.

-John

Fiberglass sanding / primer filler

ALL raw fiberglass parts should be completely sanded with 80 grit paper with no remaining mold "smooth" parts. Molded FG parts will all have mold release contaminants. You need to have a rough surface for your primer-filler to grip to, otherwise, you are just asking for paint delamination down the road. Throughly clean/wipe down to remove ALL dust.

The best way to fill pinholes with primer-filler is to spray on the primer, then squeege the primer back and forth on the surface for the first coat, to work the primer INTO the holes. Otherwise, the primer covers the hole, not filling it... when you sand down the primer, the holes will still be there.

Dry sand first coat of primer with 220 grit, respray then wetsand with 400 grit. Don't use that red laquer spotting putty for filling "large" defecits, it shrinks too much and can delam over time.